Applied Math 20S (Fall 2008)

A window through the walls of our classroom. This is an interactive learning ecology for students and parents in my Applied Math 20S class. This ongoing dialogue is as rich as YOU make it. Visit often and post your comments freely.

Thursday, January 22, 2009

Today we worked on surface area, volume, and circumference of a sphere. The questions we worked on were:

1. The surface area of a sphere is 1256 sq. cm. what is it's circumference?

2. The surface area of a sphere is 1256 sq. cm. what is its volume?

1. The volume of a sphere is 7234.56 cubic cm. What is its radius?

2. The volume of a sphere is 7234.56 cu. cm. What is its circumference?

3. The volume of a sphere is 7234.56 cu. cm. What is its surface area?

Also he gave us a few tips for our exam. He said that the question numbered 1, about the radius, is not going to be on the exam, but you should do it anyways. He told us one more thing as well. that in order to get # 2 we were to do # 1 first. Be warned though that we are having to do triginometeric figure reviews tomorrow.

Wednesday, January 21, 2009

Hey everybody, in today's class we did some problems one scale factors we also talked a little about QUADRILATERALS - Any 4 sided figure ( Trapezoid, Parallelogram, Rectangle, Rhombus and the Square).

Back to scale factors, Scale factors ALWAYStalks about length. You have to be careful and watch when your doing problems on scale thou because area is NOT length. One of the problems we did was we had to find the area of a trapezoid. In this problem the scale was 1:20 so you would multiply your area by 20 squared not 20 because area is NOT length. Its the same with volume you would multiply it by 20 cubed. An easy way to remember this is

Example :

Length

1:4

Area

1 squared : 4 squared

1: 16

Volume

1 cubed : 4 cubed

1: 64

You also have to remember to indicate your units of measurement and weather its squared or cubed. So for example cm squared, and always remember to show your work.

The slides from today's class are posted below with all the problems we did and the homework assignment.

Tuesday, January 20, 2009

So im a little bit late on this scribe post but I am required to do it anways so here it is. This is the post for the class of the 19th by the way. Above is a question Mr.K gave us that most of us had trouble doing that day, but with his help we figured it out. He just basically put stuff that had the same value over eachother and worked with it until he found his answer.

We also had a quiz on measurement that everyone seemed to have had a good grasp on because we all good exceptionally high marks. The quiz focused on alot of questions having to do with converting different units of measurements like for instance converting CM into M, and stuff like that. Then there were a couple of questions focusing on the area and perimeter of a shapes, but previous posts have covered that topic.

In the beginning of class we discussed and reviewed from yesterday's materials. All that stuff is on the lower slides below which is called MORE ON MEASUREMENT.

After that we went through the questions that were on the previous slide. Our teacher explained that if the question asked to convert 7 cm 2 to mm we had to go through a series of steps. Well think of it as big square and being cut up into smaller units than it originally was but the same square being the same way it was. After, 2 sides which are the top and the right side was 10 mm. So now you would cut 10 little squares on both sides to the point were who would have 100 littlesquares. Now picture that and now you have 1 cm 2Now basically multiply 100 mm by 7 and you get 700mm2*DONT FORGET THE SQUARE!*

But all it all comes down to an easier way and the easier way is to multiply 7 by 100 and you get 700mm2

After that discussion we had moved on and were talking about volume. Our teacher explained that volumemeasures width, length and depth. Volume is also like square but instead of using square we use cubed. Cube is then recognized as 3 instead of 2. It is basically the same steps but the only thing different about it is to change square to cubed.